From 4c1c1875fc44008e4a8816c6b6aac1e214aba017 Mon Sep 17 00:00:00 2001
From: Christoph Urlacher <christoph.urlacher@protonmail.com>
Date: Sun, 8 Mar 2026 14:30:43 +0100
Subject: [PATCH] baremetal: provide os_mmap/os_mremap for wamr
 aot_load_from_aot_file

---
 .../shared/platform/baremetal/platform_init.c | 55 ++++++++++++++++++-
 .../platform/baremetal/platform_internal.h    |  5 +-
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/core/shared/platform/baremetal/platform_init.c b/core/shared/platform/baremetal/platform_init.c
index 996f6dcb..c14cd93e 100644
--- a/core/shared/platform/baremetal/platform_init.c
+++ b/core/shared/platform/baremetal/platform_init.c
@@ -92,16 +92,67 @@ bh_log_proc_mem(const char *function, uint32 line)
  * mman
  ****************************************************/
 
+// NOTE: We need os_mmap for aot_load_from_aot_file
+//
+// Stacktrace:
+// #5  0x0805e5c1 in os_mmap
+// #6  0x080524d3 in loader_mmap
+// #7  0x08059294 in create_sections
+// #8  0x08059553 in load
+// #9  0x0805966b in aot_load_from_aot_file
+// #10 0x08048c34 in wasm_runtime_load_ex
+// #11 0x08048cff in wasm_runtime_load
+// #12 0x08048112 in main
+
+#define MMAP_SPACE_SIZE (2 * 1024 * 1024)
+static uint8_t mmap_space[MMAP_SPACE_SIZE];
+static size_t mmap_offset = 0; // Free space begins here
+
+static size_t
+align_up(size_t x, size_t a)
+{
+    // a is a power of two, e.g., 8:
+    // x+a-1: Shift value upwards to the next alignment "bucket"
+    // a-1: 00000111, ~(a-1): 11111000 - Clears the lower bits/alignment
+    // remainder
+    return (x + a - 1) & ~(a - 1);
+}
+
 void *
 os_mmap(void *hint, size_t size, int prot, int flags, os_file_handle file)
 {
-    return NULL;
+    // Free space begins here (aligned)
+    size_t start = align_up(mmap_offset, PAGE_SIZE);
+
+    // How much we're mapping
+    size_T end = start + align_up(size, PAGE_SIZE);
+
+    if (end > MMAP_SPACE_SIZE) {
+        return NULL;
+    }
+
+    void *ptr = &mmap_space[start];
+    mmap_offset = end;
+
+    return ptr;
 }
 
 void *
 os_mremap(void *old_addr, size_t old_size, size_t new_size)
 {
-    return NULL;
+    // Map the new size
+    void *new_addr = os_mmap(NULL, new_size, 0, 0, -1);
+    if (!new_addr) {
+        return NULL;
+    }
+
+    // Copy the old memory to the new mapped address
+    if (old_addr) {
+        size_t copy_size = old_size < new_size ? old_size : new_size;
+        memcpy(new_addr, old_addr, copy_size);
+    }
+
+    return new_addr;
 }
 
 void
diff --git a/core/shared/platform/baremetal/platform_internal.h b/core/shared/platform/baremetal/platform_internal.h
index b0ac7f6e..615d79f7 100644
--- a/core/shared/platform/baremetal/platform_internal.h
+++ b/core/shared/platform/baremetal/platform_internal.h
@@ -74,11 +74,12 @@ os_get_invalid_handle(void)
     return -1;
 }
 
+#define PAGE_SIZE 4096
+
 static inline int
 os_getpagesize()
 {
-    // TODO: What pagesize? 65536?
-    return 4096;
+    return PAGE_SIZE;
 }
 
 // void *